Cannot read property 'filter' of undefined

[sibelius]

Do you want to request a feature or report a bug?
bug

What is the current behavior?
it is breaking with the following error:

TypeError: Cannot read property 'filter' of undefined

      at node_modules/mongoose/lib/model.js:3251:32
      at parallelLimit (node_modules/mongoose/lib/helpers/parallelLimit.js:15:12)
      at Function.Object.<anonymous>.Model.$__insertMany (node_modules/mongoose/lib/model.js:3245:3)
      at process.nextTick (node_modules/kareem/index.js:369:33)

If the current behavior is a bug, please provide the steps to reproduce.

Everything worked well on 5.6.11 but it broke on 5.6.12

What is the expected behavior?
it should not break

What are the versions of Node.js, Mongoose and MongoDB you are using? Note that "latest" is not a version.
mongoose: 5.6.12
node: 10.15.0
mongo: v4.0.5

[nadr0]

Happened to me too. I rolled out the version with 5.6.12 and it reported the same error. I have to roll back to 5.6.11 and things are back to normal.

[vkarpov15]

@sibelius not a very helpful bug report - please provide code samples next time. Stack traces are typically not very helpful 👎

[sibelius]

the error happens when you are saving many documents at once

the error is here

https://github.com/Automattic/mongoose/blob/master/lib/model.js#L3251

const docAttributes = docs.filter(function(doc) {
return doc != null;
});

docs is null in parallelLimit

maybe a regression from here

03dfc6a

[sibelius]

this could be the cause of the bug

03dfc6a#diff-af13acd1e8d4818a7336e3dd68eb5efbR15

if fns.length === 0), it won't have either error nor docs

[nadr0]

@vkarpov15

I cannot share my exact snippet of code that failed but it failed in this way.

// inside some async function ...
try {
  const arr = [];
  const result = await myModel.insertMany(arr);
} catch (e) {
  console.log(e);
}

I tried to do insertMany (https://mongoosejs.com/docs/api.html#model_Model.insertMany) with an empty array and I got the same error @sibelius got.

[vkarpov15]

Looks like @sibelius fixed this in his latest #8130. @nadr0 please upgrade to mongoose 5.6.13 for the fix.